a. [f. prec. + -AL 1.] Of the nature of apagoge; by reductio ad absurdum.
1706. Phillips, Apagogical Demonstrations.
1734. Berkeley, Analyst, § 25. 41. Why any other apagogical Demonstration, or Demonstration ad absurdum should be admitted.
1860. Fleming, Voc. Philos., s.v. Ostensive, A proof … is indirect, or apagogical when it evinces the truth of a thesis through the falsehood of its opposite, that is, mediately.
